Full-Stack Engineer

Who we are

Sapien is the engine behind the world’s most important companies. We build agents that learn how a business works from its financial and operational data: its language, operations, and economics. That understanding helps people find opportunities, make better decisions, and act.

We work with complex businesses, from manufacturers and restaurant groups to the Fortune 500. Teams at companies including Bayer, Cooper Standard, Blink Charging, Carlex, and Odeko use Sapien to understand their businesses and improve how they run. Our ambition is to build the self-optimizing company by making its people and systems dramatically more capable.

We’re headquartered by Madison Square Park in NYC, with $15M+ raised and backing from General Catalyst, Neo, and operators from OpenAI, Google, Microsoft, Ramp, and Stripe. We’re bringing together AI researchers, engineers, and operators to build intelligence for the people who build everything else.

The role

You'll build features end-to-end for Sapien's core platform. This means taking a feature from design through frontend implementation, backend APIs, database changes, and agent integration. You own the full experience and make it work.

This is a role where you'll balance shipping new capabilities with keeping the platform stable and performant. You'll work directly with customers, see how they use what you build, and iterate based on real feedback.

What you'll do

• Build features that make Sapien a daily driver for finance and operations teams. Design experiences that pull users in every day because the platform is proactively surfacing insights, catching issues before they become problems, and making their work faster and smarter.

• Design interfaces that make complex agent operations understandable and controllable for finance and operations teams who aren't technical.

• Implement human-in-the-loop systems where users can give feedback, correct agent mistakes, and teach the system about their specific business processes. Build the feedback loops that make agents smarter over time.

• Make product and technical decisions: what should this feature do, how should the UI work, what's the right database schema, which technologies should we use. You're not just implementing specs, you're figuring out what to build.

What we're looking for

• Comfort with modern web technologies: React, TypeScript, Python, SQL, and common backend frameworks. You don't need to be an expert in everything, but you should be able to work across the stack.

• Product mindset. You think about user experience, not just implementation. You've iterated on features based on how people actually use them.

• Ability to work with ambiguity. You can take a rough problem statement, talk to the right people, and figure out what actually needs to be built.

• CS degree or equivalent experience. We care most about what you've built.

How you work (values we care about)

• Adaptability: You move fluidly between design, frontend, backend, and customer conversations. You're comfortable in unfamiliar territory and can shift contexts quickly.

• Ownership: You see features through. You don't stop at "it works on my machine." You deploy it, monitor it, fix issues that come up, and make sure it actually solves the problem

• Opinionated: You have strong views on technical decisions and product tradeoffs. You push back when something doesn't make sense and help the team make better choices.

• Mission-driven: You understand that every interface decision impacts whether finance teams trust and adopt AI. You care deeply about building products that transform how businesses run.

• Collaborative excellence: You make the team better. You share knowledge, give thoughtful code reviews, and bring new ideas that improve how we all work.